Split heat ??

Question
Hello and thank you for your help on this board!
My concern is my 3 year old Yorki/Chi. Had a litter (only one pup) in April, displayed normal heat "symptoms" about 2 weeks ago along with another intact female (who is now pregnant). The concern is the bleeding stopped sooner than it should have, after only maybe 5 days. She didn't seem as "flirty" with our males as she usually is, but they are quite "insistant" and she did accept his mating. I thought the timing was a little off but wasn't too concerned (as I was wrong with timing her before, so I was "trusting" my pretty succesful male to know the right time). I was only allowing male limited access to her (otherwise he would be at her ALL day)but they did tie once per day over the course of like 10 days. Thought for SURE she would be pregnant. Last night I notice she is lightly spotting. No temp, good appetite, acting fine. Males still want her but being kept apart.  
I am wondering if this could be a split heat or some other hormone problem? I am aslo watching for infection and she will be at vet Monday morning for a complete check. Just wanting more info and wondering if this could also be a "dormitory" affect type of situation also?
Can't figure this one out!
Thanks for any info or suggestions ~
Kelly

Answer
Hi Kelly

You are right on tract with all your assumptions.  Housed with other females her cycle could have started a bit early causing the split heat, an infection would cause some slight spotting as would a hormonal imbalance.  

The vet will better able to assess the problem as it could be any or all of the above.

Good luck